1. Technical Field
The present invention relates to a semiconductor device, and more particularly, to a printed circuit board in which a semiconductor chip is molded and a package using the printed circuit board.
2. Description of the Related Art
Generally, a semiconductor package is manufactured through a sawing process, a die attaching process, a wire bonding process, and a molding process. The molding process is a process of sealing a semiconductor chip using a molding resin to protect the electrical characteristics of the semiconductor chip and to mechanically protect the semiconductor chip.
The molding is performed using a mold that determines the shape of a package. The main body of the mold is formed by filling a molding compound (resin) in a molding cavity that is formed with upper, middle, and lower plates.
In the molding process, a molding region of a printed circuit board is molded by filling a resin in the molding cavity by supplying the resin through a mold gate after the molding region of the printed circuit board, which includes a semiconductor chip for which a die attach process and a wire bonding process are completed, is located in the molding cavity of the mold. At this point, at the same time that the resin is supplied to the molding cavity through the mold gate of the mold, air present in the molding cavity is vented to the outside through an air vent included on the mold.
When annealing the mold so as to harden the resin, the air vent can be misaligned on the printed circuit board due to the thermal expansion coefficient difference between the printed circuit board and the mold. In a package on package (POP) device, a ball land, which is a connection terminal, is present on the upper side of a lower package that is combined with an upper package. However, when molding is performed, if the air vent is misaligned, a path of the air vent can pass over the ball land or, if the resin is pushed out through the air vent, the ball land can be contaminated by the resin. FIG. 1 is a photo image of a printed circuit board in which a ball land is contaminated by a resin. In FIG. 1, it can be seen that a molding resin 15 passes directly over the circular ball land 20 on a printed circuit board 10. As such, if the ball land 20 becomes contaminated by the molding resin 15, a contact failure between a contact terminal of the upper package and the ball land 20 can occur.
Also, when the mold separates from the printed circuit board after an annealing process of the resin is finished, a photo sensitive resist (PSR), which is a protective layer for the printed circuit board, can be detached due to the air vent. As a result, the detached PSR can block the air vent, and thus, air in the molding cavity cannot be vented to the outside in a subsequent process, thereby causing an unstable molding process.